Hydraulic pallet lift truck



March 17, 1959 G. J. DAVIS 2,877,982

HYDRAULIC PALLET LIFT TRUCK Filed Aug. 31, 1956 Fig. 3g 4 United StatesPatent 2,877,982 HYDRAULIC PALLET LIFT TRUCK George J. Davis, Atlanta,Ga. Application August 31, 1956, Serial No. 607,329 2 Claims. (Cl.254-10) This invention relates to lift trucks.

It is an object of the present invention to provide a hydraulic palletlift truck particularly adapted for storage warehouses and which has atleast a 3,000 pound capacity. I

It is another object of the present invention to provide a hydraulicpallet lift truck of the above type which is operated by a foot pedaland wherein the device includes heavy springs for lowering the liftrapidly.

Other objects of the invention are to provide a hydraulic pallet lifttruck bearing the above objects in mind, which is of simpleconstruction, has a minimum number of parts, is inexpensive tomanufacture and eificient in operation and use.

For other objects and for a better understanding of the invention,reference may be had to the following detailed description taken inconnection with the accompanying drawing, in which:

Figure l is a top plan view of a preferred embodiment of the presentinvention;

Fig. 2 is a side elevational view thereof showing in phantom the raisedposition of the sub-platform;

Fig. 3 is a vertical sectional view taken along the line 3-3 of Fig. 1;

Fig. 4 is a view looking along the line with the housing removed;

Fig. 5 is a vertical sectional view taken along the line 5-5 of Fig. l;and

Fig. 6 is a vertical sectional line 6-6 of Fig. 5.

Referring now more in detail to the drawing, a U- shaped main frameindicated generally at 10 is provided and includes a U-shaped end plate11 (Fig. 4) having the braces 12 and which is longitudinally spaced andparallel to the end plate 13, suitable brace means being provided forconnecting the plates 11 and 13.

The main frame 10 includes a pair of laterally spaced, parallel sideportions 14 of U-shaped cross section fixedly connected at one end tothe end portion of the frame 10 and supported at their ends remote fromthe plates 13 by the wheels 15 and axle 16 (Fig. 5), ball bearingmountings being employed.

The platforms 17 are fixedly mounted on the ends of the plate 11 andsupport the U-shaped handle 18 as well as mounting therebelow thecasters 19 of ball bearing construction. Braces 20 reinforce theconnection of the handle 18 to the pladorm 17, while the braces 21reinforce the connection of the platforms themselves to the plate 13.

A supporting plate 22 is mounted intermediate the plates 11 and 13 (Fig.3) being inclined upwardly and forwardly and mounting thereon thehydraulic jack indicated generally at 23. The hydraulic jack 23 includesthe foot pedal 24 as well as the release pedal 25, being of conventionalconstruction.

A transverse shaft 26 is fixedly mounted at the upper end of the jackand is urged downwardly by the coil springs 27 having their lower endsconnected to the base plate 22.

A sub-platform is provided and includes a pair of side members 28 ofinverted U-shaped cross section hav- 4-4 of Fig. 3

view taken along the 2,877,982 Patented Mar. 17, 1959 ing bevelled ends29 to facilitate their insertion under the object to be lifted, the sideportions 28 being adapted to fit downwardly in nesting relationship overthe side portions 14 of the main frame 10 (Fig. 5). The side portions 28of the sub-platform are connected at their other end by the transverseplate 30 as well as the braces 31 and 32.

A pair of laterally spaced links 33 are rotatably mounted at their lowerends at each end of the side members 14 by means of the bearing members34, the

links 33 intermediate their ends being connected by the spacer bolts 35(Fig. 6). The upper ends of the pairs of links 33 are pivotallyconnected to the undersurface of the central portions of the sideportions 28 of the sub-platforms by means of the bearing members 36.

As shown in Fig. 1, two pair of laterally spaced stationary links 37 arefixedly connected to the central portion of the plate 30 and arepivotally connected at their other ends to the lift rods 38 by means ofthe pins 39, the lower ends of the lift rods 38 being received betweeneach pair of spaced links 37. The upper ends of the lift rods 38 arepivotally mounted on opposite ends of the shaft 36 by means of thecollars 40. The plate 13 is provided with the laterally spaced cutouts41 (Fig. 4) which receive therethrough the links 37.

A hollow, substantially trapezoidal shaped housing 42 encases thehydraulic pump 23 between the platform 17, being open at the lower endand suitably secured to the plates 11 and 13, he housing 42 having anopening 43 which receives outwardly therethrough the pedal 24. A coilspring 44 is connected at its upper end to the top of the housing 42 andat its lower end to the foot pedal 24 whereby to automatically raise thesame after it has been depressed. It will be seen that the lift rods 38when the hydraulic pump 23 is in the lowermost position will support thesub-platform and the side portions 28 thereof slightly above the sideportions 14 of the main frame with the beveled ends 29 being adapted topass under the object to be lifted in a manner well known to thoseskilled in the art. In this case, the links 33 will be disposed in theinclined position of Fig. 6.

In operation, as the foot pedal 24 is pumped, the transverse shaft 26will be raised by the hydraulic pump 23 to the dotted line position ofFig. 4, lifting the subplatform vertically and towards the housing 42about the bearing members 34 and 36, at which point the links 33 will besubstantially vertical. Upon depressing the release pedal 25 of thepump, the platform will return promptly to its original position underthe action of the springs 27.

While various changes may be made in the detail construction, it shallbe understood that such changes shall be within the spirit and scope ofthe present invention as defined by the appended claims.

What I claim as new and desire to protect by Letters Patent of theUnited States is:

l. A hydraulic powered lift truck comprising, in combination, asubstantially U-shaped main frame, means rotatably mounting said frameupon a supporting surface, said main frame including side portions -ofsubstantially U-shaped cross section, a sub-platform including sideportions of substantitally inverted U-shaped cross section adapted tonest downwardly upon said main frame side portions and a centraltransverse connecting portion adjacent and forwardly of the transverseportion of said main frame, first link means connecting said subplatformwith the main frame and permitting the upward movement of saidsub-platform towards the central portion of said main frame, hydraulicjack means mounted upon the central portion of said main frame on aplane extending upwardly and inwardly, a transverse shaft at the upperend of said hydraulic jack, said jack including a foot pedal for raisingthe same and a release pedal, spring means for returning said transverseshaft to its original position upon depressing said release pedal, liftrods pivotally connected to said sub-platform and to the ends of saidshaft, saidfirst link means comprising a pair of laterally spaced apartlinks pivotally connected at their lower ends to opposite ends-of theside portions of said main frame between the sides thereof, spacer meansconnecting said links intermediate their ends, said links beingpivotally connected to the under surface of said sub-platform sideportions at the central portion thereof, said first links extending atanacute angle to the main frame when the sub-platform is in the loweredposition extending away from the hydraulic jack, and two pairs oflaterally spaced apart stationary links fixedly mounted at the centralportion of the sub-platform extending toward the hydraulic jack, saidlift rods at their lower ends being pivotally mounted between each pairof said stationary links, and the upper ends of said lift rods beingpivotally mounted upon the ends of said shaft, the central portion ofsaid main frame including platforms at the opposite ends thereofextending outwardly therefrom, a U-shaped handle extending upwardly fromsaid platforms, said means rotatably mounting said main frame comprisinga pair of casters rotatably mounted below said platforms, two pairs oflaterally spaced wheels rotatably mounted at the other ends of the mainframe side portions, a substantially trapezoidal shaped hollow housingmounted on said main frame intermediate said platforms and enclosingsaid hydraulic jack, said housing having an opening receiving saidpumping pedal outwardly therethrough, a second opening receiving saidrelease pedal outwardly therethrough, and a coil spring connected at itsupper end to the top of said housing having a lower end connected tosaid pumping pedal.

2. A hydraulic powered lift truck according to claim 1, said main frameat the central portion thereof including a U-shaped outer plate fixedlymounting said platforms at the upper ends thereof and a rectangularplate spaced longitudinally therefrom and fixedly mount ing therebetweenthe base platform on which the hydraulic jack is mounted, the jackextending upwardly and away from said rectangular plate, saidrectangular plate having a pair of laterally spaced cutouts receivingsaid stationary links therethrough.

References Cited in the file of this patent UNITED STATES PATENTS1,414,163 Anthony Apr. 25, 1922 1,452,566 Martin Apr. 24, 1923 1,831,140Romine et al. Nov. 10, 1931 2,043,887 Dement June 9, 1936 2,178,647Raymond et al Nov. 7, 1939 FOREIGN PATENTS 1,018,732 France Oct. 15,1952

